The present invention relates to a developer conveying apparatus that conveys a developer, and relates to a developer storage container and an image forming apparatus using the developer conveying apparatus.
In a general electrophotographic image forming apparatus, a residual toner may remain on a surface of a photosensitive drum after a transferring process of a toner image. Such a residual toner is removed from the surface of the photosensitive drum using a cleaning member, and is collected by a toner collection apparatus provided in the image forming apparatus.
In this regard, it is conceivable that the toner collection apparatus can have a storage container that receives and stores a freely falling toner. However, in such a case, it is necessary to increase a size of the storage container in a vertical direction (i.e., a direction of gravity) in order to store a sufficient amount of the toner. Practically, it is difficult to provide a space for such a storage container in the image forming apparatus.
Therefore, there is proposed a toner collection apparatus having a storage container which is elongated horizontally. A toner conveying mechanism (for example, a spiral) is provided inside the storage container, which rotates to convey the toner in a horizontal direction (see, for example, Japanese Laid-open Patent Publication No. 2006-162941).
In this regard, when a large amount of the toner is stored in the storage container, the toner may be accumulated locally at a downstream part of the storage container to high density at an early stage. Such a local accumulation of the toner may increase a load on the toner conveying mechanism, and therefore the toner conveying mechanism may stop conveying even when the storage container is not filled with the toner. Therefore, it is demanded to enhance efficiency in the storage of the toner.